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[/] [or1k/] [trunk/] [newlib-1.10.0/] [newlib/] [libc/] [string/] [strlen.c] - Diff between revs 1010 and 1765

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Rev 1010 Rev 1765
/*
/*
FUNCTION
FUNCTION
        <<strlen>>---character string length
        <<strlen>>---character string length
 
 
INDEX
INDEX
        strlen
        strlen
 
 
ANSI_SYNOPSIS
ANSI_SYNOPSIS
        #include <string.h>
        #include <string.h>
        size_t strlen(const char *<[str]>);
        size_t strlen(const char *<[str]>);
 
 
TRAD_SYNOPSIS
TRAD_SYNOPSIS
        #include <string.h>
        #include <string.h>
        size_t strlen(<[str]>)
        size_t strlen(<[str]>)
        char *<[src]>;
        char *<[src]>;
 
 
DESCRIPTION
DESCRIPTION
        The <<strlen>> function works out the length of the string
        The <<strlen>> function works out the length of the string
        starting at <<*<[str]>>> by counting chararacters until it
        starting at <<*<[str]>>> by counting chararacters until it
        reaches a <<NULL>> character.
        reaches a <<NULL>> character.
 
 
RETURNS
RETURNS
        <<strlen>> returns the character count.
        <<strlen>> returns the character count.
 
 
PORTABILITY
PORTABILITY
<<strlen>> is ANSI C.
<<strlen>> is ANSI C.
 
 
<<strlen>> requires no supporting OS subroutines.
<<strlen>> requires no supporting OS subroutines.
 
 
QUICKREF
QUICKREF
        strlen ansi pure
        strlen ansi pure
*/
*/
 
 
#include <_ansi.h>
#include <_ansi.h>
#include <string.h>
#include <string.h>
#include <limits.h>
#include <limits.h>
 
 
#define LBLOCKSIZE   (sizeof (long))
#define LBLOCKSIZE   (sizeof (long))
#define UNALIGNED(X) ((long)X & (LBLOCKSIZE - 1))
#define UNALIGNED(X) ((long)X & (LBLOCKSIZE - 1))
 
 
#if LONG_MAX == 2147483647L
#if LONG_MAX == 2147483647L
#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
#else
#else
#if LONG_MAX == 9223372036854775807L
#if LONG_MAX == 9223372036854775807L
/* Nonzero if X (a long int) contains a NULL byte. */
/* Nonzero if X (a long int) contains a NULL byte. */
#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
#else
#else
#error long int is not a 32bit or 64bit type.
#error long int is not a 32bit or 64bit type.
#endif
#endif
#endif
#endif
 
 
#ifndef DETECTNULL
#ifndef DETECTNULL
#error long int is not a 32bit or 64bit byte
#error long int is not a 32bit or 64bit byte
#endif
#endif
 
 
size_t
size_t
_DEFUN (strlen, (str),
_DEFUN (strlen, (str),
        _CONST char *str)
        _CONST char *str)
{
{
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
  _CONST char *start = str;
  _CONST char *start = str;
 
 
  while (*str)
  while (*str)
    str++;
    str++;
 
 
  return str - start;
  return str - start;
#else
#else
  _CONST char *start = str;
  _CONST char *start = str;
  unsigned long *aligned_addr;
  unsigned long *aligned_addr;
 
 
  if (!UNALIGNED (str))
  if (!UNALIGNED (str))
    {
    {
      /* If the string is word-aligned, we can check for the presence of
      /* If the string is word-aligned, we can check for the presence of
         a null in each word-sized block.  */
         a null in each word-sized block.  */
      aligned_addr = (unsigned long*)str;
      aligned_addr = (unsigned long*)str;
      while (!DETECTNULL (*aligned_addr))
      while (!DETECTNULL (*aligned_addr))
        aligned_addr++;
        aligned_addr++;
 
 
      /* Once a null is detected, we check each byte in that block for a
      /* Once a null is detected, we check each byte in that block for a
         precise position of the null.  */
         precise position of the null.  */
      str = (char*)aligned_addr;
      str = (char*)aligned_addr;
    }
    }
 
 
  while (*str)
  while (*str)
    str++;
    str++;
  return str - start;
  return str - start;
#endif /* not PREFER_SIZE_OVER_SPEED */
#endif /* not PREFER_SIZE_OVER_SPEED */
}
}
 
 

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